I think that is the kind of dress that you see very cheap rip-offs of in shops like H&M, though I don't doubt the material and fit is much, much nicer. It is pretty but I honestly don't love it - it looks like it is two different dresses, neither one thing nor the other...and I don't think it's worth that kind of money. What's it made of? If it's polyester, I wouldn't.
It's worth looking at Mint Velvet. You can get 20% off dresses by entering summerdress in the promo box and they do free returns, I believe.
This is a nice one, would look great accessorised well
Silk too! Don't know your size but 8, 10 and 12 still in stock. Just over a hundred quid with discount.
www.mintvelvet.co.uk/anisa-print-silk-maxi-dress/dresses/mint-v/fcp-product/2832
This Jigsaw one is £225. It is really beautiful and would look really nice accessorized with muted golds (clutch and sandals). I know their stuff runs long though so you'd be reliant on a good seamstress for hemming.
www.johnlewis.com/jigsaw-dapple-leaf-maxi-dress-dark-green/p443786
I think this Monsoon one is nice (£119)
uk.monsoon.co.uk/view/product/uk_catalog/mon_13.11/3531026110
Check out Ted Baker's site too...dear but they do a fair few maxi dresses.
If none of these float your boat, I'd buy the one you love. It will be an item you can come back to again and again. Alternatively, if it's a popular dress you could buy, wear it to the wedding, get it dry-cleaned and put it on Ebay.
Hope you find something. Let us know ... 